Neodymium Nd

Discovery

Neodymium was born, together with praseodymium, from didymium. In 1885 Carl Auer von Welsbach patiently fractionally crystallised didymium salts and split them into two new elements, naming the one that formed pink salts neodymium.

Pure neodymium metal was obtained only around 1925. It became an industrial material after the mid-twentieth century, when ion exchange and solvent extraction made it practical to separate the rare earths efficiently.

In the early 1980s Masato Sagawa at Sumitomo Special Metals in Japan and researchers at General Motors in the United States independently developed magnets based on neodymium, iron and boron (Nd₂Fe₁₄B). Far stronger than earlier magnets, they enabled the miniaturisation of countless electronic devices.

Origin of the name

The name combines the Greek neos, "new", with didymos, "twin", meaning "new twin", because it was newly separated from didymium. The symbol is Nd.

Main uses

• Neodymium magnets: they are much stronger than ferrite magnets of the same size and drive electric and hybrid vehicle motors, wind turbine generators, hard disk head actuators, phone speakers and vibration motors, and wireless earbuds. Small amounts of dysprosium or terbium are often added so the magnets keep their strength at high temperatures.
• Lasers: neodymium-doped YAG crystals emit infrared light at 1,064 nm and are used widely in metalworking and medicine. Neodymium glass lasers power giant laser facilities for fusion research.
• Glass colouring: neodymium glass looks violet or blue depending on the lighting and is also used in didymium safety glasses.

Isotopes

Natural neodymium has seven isotopes, neodymium-142, -143, -144, -145, -146, -148 and -150, with neodymium-142 the most abundant. Neodymium-144 undergoes alpha decay but has a half-life of about 2 × 10¹⁵ years, and neodymium-150 decays extremely slowly by double beta decay.

Samarium-147 alpha-decays to neodymium-143, and samarium–neodymium dating based on this pair is used to determine the ages of meteorites and ancient rocks and to study the evolution of Earth's mantle.

In everyday life

Neodymium is extracted from bastnäsite and monazite. China dominates not only mining but also magnet manufacturing, so neodymium is often at the centre of supply-chain debates.

Neodymium magnets are small but extremely strong. Two of them snapping together can pinch fingers or shatter and send out sharp fragments. It is especially dangerous if a child swallows several small magnets, because they can attract each other through the intestinal walls and cause perforations. They should be kept away from pacemakers, and it is wise to keep them away from credit cards and mechanical watches.